1. Field of the Invention
The invention pertains to a novel positive control fill valve, particularly suited for application in the dispensing of flowable materials in hygienic or sanitary dispensing operations, such as used in the food, medical and pharmaceutical industries. More particularly, the novel fill valve assembly provides for the positive control over the dispensing of a wide range of liquids having varying degrees of viscosity by utilizing a positive control valve activated by a pneumatically activated piston, having a substantially cylindrical shaped sealing head in combination with a tapered cylinder for providing a positive control over the dispensation of fluids dispensed through the fill assembly.
The novel fill assembly includes at one end, a reservoir for activating the positive controlled product dispensing piston and at the other end, an outlet having a tapered sealing seat for dispensing the product and seating the sealing head of the product dispensing piston. A leak detection port for positively identifying seal failure is disposed between a positive seal means having a first seal disposed between the leak detection port and the reservoir for activating the product dispensing piston and a second seal disposed intermediate the leak detection port and the product dispensing outlet. The novel hygienic and sanitary fill valve assembly further includes flanges for connecting the reservoir which in the best mode is a chamber for activating the product dispensation piston with a corresponding flange around the bottom of the dispensation chamber to allow the novel fill valve assembly to be cleaned or sterilized in place, as is preferred in the pharmaceutical, medical and food processing industries.
The flanges for connecting the product dispensing outlet from the pneumatic activation chamber, as well as for the cleaning in place mechanism, provide a hygienic and sanitary environment, which allows for effective cleaning of the valve, piston and internal components of the novel fill valve assembly to prevent the build up of contaminants in threads, seams, welds, or other surface irregularities in the novel fill valve assembly. The novel fill valve assembly is typically constructed of high quality stainless steel or other material that is compatible with food processing equipment.
2. Description of Related Prior Art
The prior art includes many types of product dispensation valves for dispensing product. Many of these prior art valves do not include a tapered sealing seat in combination with a pneumatically activated piston for providing a positive shut-off of viscous fill materials. Many of the prior art valves result in a dripping or sloshing of a fill material around the filled container. None of the prior art includes a tapered seat in combination with a substantially cylindrical sealing head for positively shutting off the flow of dispensed material by seating the substantially cylindrical head of a product dispensing piston in a tapered seat when the valve is in the closed position and the placement of the sealing head is in the flow path of the dispensed product to circulate the fill material around the sealing head to prevent sloshing of the fill material during dispensation. Further, none of the known prior art dispensing valves includes a novel leak detection port disposed intermediate the ends of the product dispensing piston in combination with a novel positive seal means which includes, at one end, a seal between the piston activation chamber and the leak detection port and a second seal disposed between the product dispensation chamber and the leak detection port so that failure of the seal at either side of the leak detection port results in a positive identification of the exact portion of the seal that is damaged.
The best known prior art fill assembly valves typically employed in the food processing industry are not known to have a leak detection port in combination with a piston with a tapered seat and nozzle combination for positively dispensing liquid products without sloshing or dripping.
The best known fill valve assemblies uncovered in the course of the prior art search is Copas, et al. U.S. Pat. No. 4,518,021 which discloses a similar type of flanged fill machine having a product dispensing nozzle with a side inlet. The nozzle includes a tapered nozzle end and product,dispensing piston in the up position does not remain in the flow to prevent sloshing and does not employ a sealing head forming a dual function. Further Copas, et al. does not contain a leak detection port or a pneumatic means to positively control the dispensation of the product or provide a system for assuring that the fluid activation of the product dispensing piston would not contaminate the fill product material to assure the highest quality of product dispensing and handling.
The prior art includes also a variety of leak detection ports for a variety of applications. Leak detection ports have been provided for gas flow applications such as Matthews U.S. Pat. No. 3,999,932, Kurtz, et al U.S. Pat. No. 4,648,874 and Steeper U.S. Pat. No. 4,888,979. None of these prior art patents teach or suggest the utilization of a leak detection port in a filling machine such as Copas, et al. U.S. Pat. No. 4,518,021. Further, none of the known prior art leak detection port devices utilizes a double seal arrangement around a piston to identify the failure of a seal to prevent the contamination of a fill product. The closest of the known leak detection port apparatus is Steeper U.S. Pat. No. 4,888,979, which pertains to leak detection across an O-ring sealing a flanged connection. This leak detection provided in Steeper U.S. Pat. No. 4,888,979 pertains to leak detection radially along the O-ring as opposed to axially as is provided in accordance with the novel fill valve assembly of the invention.
A novel sanitary fill valve assembly providing positive control over dispensed liquids and preventing contamination between the dispensed liquids and the means for activation of the piston is provided by a novel leak detection port for providing the positive identification of seal failure before contamination of a dispensed product. The novel hygienic fill valve assembly includes, at one end, a fluid chamber for providing the positive control over a piston for providing for the dispensation of a fill material through a product outlet chamber to a fill material outlet or nozzle disposed at the other end for dispensing the fill product and a product inlet port disposed intermediate the fluid chamber and the product dispensation outlet or nozzle. A positively controlled fluid activated piston is disposed intermediate the fluid chamber and the product outlet chamber, which includes a substantially cylindrical sealing head, which provides positive sealing by mating with a tapered sealing seat in the product outlet chamber. In the best mode of the invention, the fluid chamber for activating the product dispensing piston is pneumatically controlled.
A first seal is provided intermediate a leak detection port and the fluid chamber and a second seal is provided intermediate the leak detection port and the product outlet chamber to provide positive identification of seal failure and to prevent contamination of the product with air or fluids which activate the fluid control product dispensing piston. The leak detection port in combination with different fluids, i.e., gas and liquid or fluids of different color, serves to positively identify the defective seal and provide a failsafe seal system to prevent contamination. In the preferred application of the invention, the product dispensing piston is activated by air as the fluid activation means and in the preferred application the identification of the defective seal is provided by the release of a fill liquid or a gas from the leak detection port while preventing cross contamination.
The novel positive control fill valve assembly can include an optional nozzle having one or more fluid ports provided in the outlet nozzle. In this embodiment of the invention, the substantially cylindrical seating head is designed to mate with the tapered outlet so that fluids remaining in the channels of the nozzle are positively controlled by the seating of the cylindrical shaped piston head in the tapered nozzle head so that the viscosity of the fluid in combination with the size and number of channels in the nozzle prevent fluids from dripping much in the same manner as trapping liquid in a straw prevents fluid displacement in the straw. The combination of the sealing head together with the tapered seat in proximity to the channels of the nozzle similarly prevents further fluid from displacing the fluid captured in the channels of the nozzle.
In another embodiment of the invention, where fluids having high viscosities and low densities such as alcohol are dispensed, the product outlet chamber, at its upper end, may include an inwardly tapering wall which provides a seat for the upper surface of the substantially cylindrical head of the product dispensing piston. In this embodiment, a nozzle with a single large opening may be utilized to provide for the dispensation of the product. In either embodiment, the substantially cylindrical head of the product dispensing piston is designed to remain in the path of flow in the product dispensation chamber to assist in the dispensation of the product into the container in a manner that prevents sloshing, spilling or dripping into a container disposed below the novel positive control fill valve assembly.
The novel positive control fill valve assembly is preferably made of stainless steel or other material that provides the highest purity and hygienic standards for the sanitary dispensing of flowable materials, particularly medicines and food products. As such, the novel positive control valve assembly is typically made of high grade non-corrosive stainless steel that is without seams, threads, welds or other surface imperfections that would allow accumulation or accretion of any particles that would result in contamination of the dispensed product. Preferably, the novel positive control fill valve assembly includes a flange disposed at the nozzle or dispensation end of the positive control fill valve assembly to allow the entire nozzle, valve, product outlet and product inlet chambers to be cleaned in place (CIP capability) by the backflow circulation of cleaning solutions through and around the tapered valve seat and cylindrical piston head of the product dispensing piston and in and through the product inlet.
The novel leak detection port provides a positive identification of the precise location of a pending seal failure that would result in contamination of the dispensed product or the fluid activation means for activating the product dispensing piston. This positive identification of the breaking down of one of the two seals in the novel positive control fill valve assembly prevents not only contamination of the piston activation fluid, but even more importantly product contamination and prevents costly recall of products packaged in prior art equipment that have been contaminated due to seal failure. This positive identification of the deterioration of the seal, as well as whether the seal is on the pneumatic side of he piston or on the product side of the piston prevents the packaging and possible shipment of contaminated products by employing a failsafe system to prevent the subsequent expensive recall of defectively filled and contaminated packaged products.